The most common congenital abnormality of this organ is Meckel's diverticulum, and its secretory cells are located in the crypts of Lieberkuhn. The distal part of this organ contains lymphoid tissue known as Peyer's patches. The flow of bile and pancreatic juice into the first part of this organ is 
The most common congenital abnormality of this organ is Meckel's diverticulum, and its secretory cells are located in the crypts of Lieberkuhn. The distal part of this organ contains lymphoid tissue known as Peyer's patches. The flow of bile and pancreatic juice into the first part of this organ is regulated by the sphincter of Oddi. This organ, which is affected by celiac disease, is divided into the duodenum, jejunum, and ileum, and is the primary site of nutrient absorption. For 10 points, name this organ whose diameter is less than the large intestine.
The most common congenital abnormality of this organ is Meckel's diverticulum, and its secretory cells are located in the crypts of Lieberkuhn.
small intestine